Answer:
D
Step-by-step explanation:
A monopolistic competition is when there are many firms selling differentiated products in an industry. A monopolistic competition has characteristics of both a monopoly and a perfect competition. the demand curve is downward sloping. it sets the price for its goods and services.
An example of monopolistic competition are restaurants
The product-variety externality: When new firms enter into an industry, competition drives price down. This increases consumer surplus. As a result, entry of firms into an industry results in a positive externality on consumers.
The business-stealing externality: When a new firm enters into an industry, existing firms lose customers and profits fall. As a result, entry of a new firm results in a negative externality on existing firms.
Markup over marginal cost is the extent of which price exceeds marginal cost
Excess capacity is when a firm is producing at a capacity that is less than what it is designed for. Excess capacity is evidenced when upon increasing output, average cost falls.